Overview

#Megastructures have captured our imagination, and no doubt scientists will start to dream up all sorts of possible megastructures around distant stars that might be detectable from earth. It is hard to say if structures that span several star systems or entire galaxies might exist, but so far, this is not mentioned in the search for alien life that might exist in other star systems.

The tag #KIC8462852 (Kepler star KIC 8462852) got people wondering if there were alien magastructures (#megastructures) out there.

The mysterious star in our galaxy is about 1,500 light-years from Earth in the constellation Cygnus.

Wild speculation about this star is that aliens built Dyson spheres, to collect energy from the sun. Other speculations are that the mega-structure might be an alien solar trust device (able to move the sun itself). There is no doubt that the list of possible alien megastructures will expand.

Dyson spheres

Alien Thrust Device #Megastructure

Planet Hunting: “Radio telescopes can see through the dust to the growing stars and planets within. The Very Large Array has imaged the rotating disks of dust and gas around some young stars that may someday form planets. However, the Atacama Large Millimeter/submillimeter Array was built with exoplanet-hunting in mind.” ~ https://public.nrao.edu/radioastronomy/exoplanets

Our own radio signals become indistinguishable from background noise after going only a few light years from earth, so we are unlikely to catch an alien version of a baseball game that is 1,500 light years away. However, very strong radio signals might be able to be received at much further distances than a few light years—the flash of an atomic bomb might send out powerful electromagnetic radiation, and some laser beams, and focused radio signals could be detected hundreds of light years away.

Introduction

This calculation is just a rough one because galaxies vary a lot. There are also things called globular clusters that can contain hundreds of thousands of stars.

In this calculation the author assumed 200 billion stars had solar systems (or half of our galaxy’s stars have solar systems). The author was wrong in that estimate: apparently nearly all the stars in our galaxy have solar systems: “Nearly Every Star In Our Galaxy Hosts At Least One Alien Planet, Scientists Say:” http://www.huffingtonpost.com/2014/03/05/stars-alien-planets-galaxy_n_4903119.html. Wow, there could be 400 billion solar systems in our galaxy…

Finally, when the author did this calculation he had no idea as to how many earth like worlds might exist in our galaxy (and there is a huge number of them): http://exoplanets.newscientistapps.com/ accessed in 2014 (There were 22,500 Earths in less than 5% of the (Milky Way) sky being scanned by Kepler telescope, which means there are 15-30 billion Earths in our galaxy.)

The chances of us being alone in the universe is starting to look very slim.

The author’s estimate below is 400 billion planets that can support life in our galaxy is still reasonable (because even in our own solar system there is more than one planet or moon that could support life now or in the past). Also life can develop in very hostile conditions on earth, and amazingly can also hitch rides on space craft. Even if a planet were not in the “life zone” mentioned in above in the Kepler telescope research, it could still develop life. The Kepler research also showed that there are often multiple planets orbiting other stars. The author’s estimate of 400 billion planets (or moons) that could support life is probably closer to what might be the case for our universe. The Kepler research is real research based on the best facts available; but they currently have no idea of how many of those 15-30 billion Earths in our galaxy will develop life, and of those which ones will develop intelligent life, because they currently have found no way to detect or to prove this from the data they have. in the future, that may change. The Kepler research does not take into account any planets that are not earth like, or might support life support life outside the “life-zone.”

Unless intelligent life is of type 2 or type 3 (and possibly type 1 if chance permits it) there is a chance it might not exist in the same galactic time as us (the dinosaurs for example did not live in the same time frame as humans–if you believe in evolution, then dinosaurs did exist at the same time as the creatures that one day would become human beings though). What that means is that it might be possible to detect the remains, or large-scale effects of long gone civilizations on other planets one day.

The author will be talking about type 0, type 1, type 2 and type 3 civilizations here. You might want to watch this video to understand exactly what that means:

The Number of Civilizations in Our Galaxy & the Universe

To calculate the numbers of advanced alien civilizations in a galaxy that want to communicate with us we use a thing called the Drake Equation. The Fermi Paradox attempts to explain why so many alien civilizations have not contacted us yet.

The author has seen a few worrying directions to the Fermi Paradox.

In one scenario if we discover life on other planets in our solar system it would be bad news for us; since it means a “filter” (of extinction) lies ahead of us. Since life is common in the Universe in this scenario: life should exist all over our galaxy. If we can’t detect life in our galaxy, the we must assume something is preventing life from reaching type 2 & 3 level civilizations–and that something might be extinction.

In another scenario the universe is a vicious place where if you are a wise civilization you will hide and keep your head down because announcing you are there will draw the attention of other (predator) civilizations. We too are a predator civilization in this definition because if we see another civilization might be a threat to us we will destroy it according to this idea. This could be a reason for why we can’t detect any civilization in our galaxy. However it can be very hard to hide the effects of a large-scale civilization that spans a planet or the entire solar system (or even the entire galaxy).

The author doesn’t agree with either of these ideas. To become a type 1 civilization we will need to find a way to not to destroy ourselves. To do that we will have to learn that conflict thinking and resource shortages (you will take my scarce resources thus you are a burden and possibly an enemy) style thinking does not work on that scale. The author believes this will only be achieved if we maintain a focus on becoming a type 2 civilization.

Finally, a type 3 or type 2 civilization that was expanding through our galaxy would probably find our system uninteresting: given there are 200 to 400 billion stars to choose from. If they discover us there is reason to think that they would simply bypass us in order to expand faster, and not waste time, energy, and materials with the chance of wars. There is also no reason why a galaxy spanning civilization would not be made up of many different type 3 civilizations since our galaxy contains at least 200, 000 of them right now.

The author suspects that we have not seen any type 3 civilizations because the evolution of such civilizations will not occur until they have gone through the type 2 civilizations evolution; and that could well last into the main sequence life time of a star and beyond. It may even be possible that a type 2 civilization might face some sort of barrier to becoming a type 3 civilization.

According to the Fermi Paradox it would take around 5 million to 50 million years to colonize the galaxy.That is not a long amount of time on the galactic time scale.

The author would also like to point out that many of our radio signals are too weak to travel and be detected across the galaxy. It’s quite possible that the nuclear tests we have conducted on earth will be detectable for quite some distance. However such signals will travel at light speeds (discussed in greater detail below). Our large civilization may also have changed the earth and it’s environment (including atmosphere) enough so that even distant telescopes might know intelligent life does exist on the earth.

Calculating the Number of Alien Civilizations in our Galaxy and in the Universe

Since the age of the universe is 13.7 billion years and our galaxy has been around for 13.2 billion years. Our sun is 5 billion years old, but will go on to live to 10 billion years old. However the earth will be destroyed by our sun when the sun is around 10 billion years old as it grows into a red giant. After that, our sun will pulsate (growing into an ever larger red giant and also dropping down to a much smaller size sun) and throw off mass until fission is not longer possible and eventually the sun will slowly cool and settle into being a white dwarf in around 12.8 billion years. Of course the life cycle of each sun if different, and so we can not assume that aliens living around another star will experience exactly the same conditions as us.

While our star may only be 5 billion years old, the earth is around 4.5 billion years old and life took 3.8 billion years to evolve to a stage where it had an intelligent life form that could communicate with other alien civilizations. Humans have only been around for a tiny fraction of that time (around 200, 000 years vs 3,8000,000,000 years for life to evolve to this stage).

We can see that life that evolved on earth took a long time. Around half the time the universe has been in existence was used to form the sun and our solar system. Life survived around our sun for around 80% of its lifetime. life on earth has also existed in the universe for 28% of the time since the big bang.

Our metal rich sun probably formed after a nearby sun exploded into a supernova.

To me the time spans discussed here would seem to indicate that if life depends on metal rich stars, then there might have been a quite period where no life existed. Of course I might be wrong about this.

We would only need one of these type 3 civilizations to expand across the galaxy, otherwise the 200, 000 type 3 alien civilizations would have to share our galaxy out among them.

This is how many type 3 civilizations would exist in our universe: 34,000,000,000,000,000

Even if a type 3 civilization took 50, 000, 000 years to colonize the galaxy, we would expect our galaxy to have one or more of these civilizations. With such a powerful and advanced civilization, we would have expected them to visit us but according to the information the author has at hand there is no solid evidence that this has occurred!

Obviously the Drake Equation has some problems or the author is not using the equation correctly for this particular case. The solution is to treat a type 3 civilizations as if it is a type 2 civilization for these particular calculations. That means we are going to have to assume that the type 3 civilizations are still hanging out in their solar system.

The Chance of pointing your telescope at one of these stars is 881,954/4*10^11= 0.0170% or you would need (on average) to check out 1/0.000170= 586,549 stars to find such a civilization.

SETI has at most examined 2,500 stars and at worst around 100 stars closely. This is not enough to tell if intelligent life exists in our galaxy. Chance of discovering intelligent life on average is 54/586,549 to 2500/586,549 or 0.009% to 0.426%. Those odds do not seem good. SETI also seems to be limiting its range to 200 light years or less. Our galaxy has a diameter of 100, 000 light years, so 200 light years is a very small area.

The author has assumed all galaxies are the same size as our own bar galaxy on average–an assumption that is bound to be incorrect (At the moment the author doesn’t know what the average size of a galaxy is, and what the average number of stars are for such a galaxy).

Summary

400,000,000,000 Stars in Milky Way

there are 881,955 advanced civilizations in our galaxy.

there are 50,000,000,000,000,000 advanced alien civilizations in the universe

We have had radio for around 100 years and SETI type experiments have been done since 1960 or for 50 years. So if an alien civilization sent radio signals to us in the last 50 years then we might be able to detect them (assuming SETI has the money to operate and receive signals). Interestingly enough SETI is scanning the local region of 100 light years and that just happens to be the distance our radio signals have traveled (100 light years).

Our own civilization according to our theory will go on to send radio signals for around another 100, 000 years or much longer if we decide to become a type 2 or 3 civilization.

There are many other disasters that can occur on earth before the sun becomes a red giant. The opposite is possible and the human race could survive if we could move the earth (using asteroids to nudge the earth once every 6000 years) and use fusion energy to replace the sun once the sun dies completely. So the survival rate of our civilization might be shorter or much longer then 100, 000 years.

The only reason the author can think of as to why we have not been visited by a type 3 civilization would be that perhaps it takes a very long time to move from a type 0 to type 3 civilization and the universe is not currently old enough to hold a type 3 civilization. But that is only my guess. To a type 3 civilization our world and solar system would most likely be insignificant. They may even look at our solar system in a similar way to the way we look at parkland or a zoo.

The author suspects that a type 2 civilization has the power to vary its stars brightness and so send signals to the rest of the galaxy that way.

In the authors opinion, the Drake Equation does need to be tweaked for the civilizations that can live longer. Our own civilization may soon be harvesting the resources of our solar system, and that makes it more possible for humanity to become a type 2 and type 3 civilization.

If we don’t find any other intelligent life in our galaxy (aliens) we might need to think about what might stop a type 1 civilization (or less) from advancing to a type 2 civilization. If it happens to be extinction, then perhaps our scientists and observers (the common person) to carefully think about how we should shape our future. Humanity should be one species in the universe that survives for a extremely long time, perhaps even beyond the chance destruction of earth, and possibly even after eventual aging (red giant) and death of our own star.